Can some of your concerns be mitigated (locally) through things like strong tenant vetting and property class selection?

Because they have to select EACH of your units for the program (not just your account) and there's no one there that can override this apparently computer generated selection criteria (trust me I've "let me speak to your managered" the hell out of this and gotten nowhere).Another thing that I don't like about Booking is that Ive got to remit taxes on my own.

Waste of time, huge room for error and zero reason for a customer to do this.....any Contractor worth his salt will have better pricing/quality/selection on the big stuff and will have guys on his crew that can do those dreaded 'parts runs' for the little stuff. 

I'd build a network of agents and owners in your select markets that work primarily with investment properties.

Choosing pre-selected materials can simplify the process.- Managing Multiple Projects Simultaneously: Handling numerous properties at different renovation stages requires effective project tracking, milestone-based contractor payments, and solid contingency plans to navigate potential delays.- Technology & Automation: Utilizing project management software, such as Buildertrend or Monday.com, enables real-time tracking of budgets, schedules, and contractor communications.

Here's an article with things to consider when selecting a cost segregation company.

We have no control of the condition of your property, if the value will appraise at where you feel it will appraise at, selecting specific appraisers, making sure the title to your property is free of any liens/judgements, what the title company will charge you, how much the AMC will charge you for an appraisal, what your property taxes will be, how much your insurance will cost you, and the list goes on.. 

An out of state turnkey option would be easy to do in parallel with this since a true turnkey option should not take much, if any effort other than selecting the right team in a market that can help you reach your goals. 

I was previously with Foundation Property Management, and they consistently mis-managed (horrible tenant selection, extreme rehab costs,...).

More likely is that they have been 'touched' by a many people providing the same service and narrow their selection to the few where they formed an favorable impression.